Prince Siegfried comes of age and celebrates his 21st birthday in the palace gardens. The next day he is to finally choose his future bride at the court ball. Near the castle, on the shores of Swan Lake, the beautiful swan girl Odette emerges from the water in the moonlight. She is actually a princess transformed by the magician Rothbart. Siegfried is overwhelmed by her beauty and immediately swears his eternal love and loyalty. The curse of the evil wizard Rothbart is now supposed to be broken, but he has his own plans for Odette.
